I know that syntax but it will make operations with your context on a 'new' recordset (self.env['object.model']).
What we want is when you are in a function 'a_function(self)' and call 'another_function(self)' in the same model (in an inherited module or not), we want to add features to current context.
We call obviously the function like :
def a_function(self):
(...)
self.another_function()
Is it possible ?